Theresa May will kick off the biggest gamble of her political life as she fights to persuade MPs to back her Brexit deal.
Facing down Labour, Conservative and DUP critics, the prime minister will insist the House of Commons must vote for her agreement to “respect the decision of the British people”.
Mrs May is due to open a marathon five-day debate on the terms of Brexit, culminating in a series of dramatic votes next Tuesday.
The fate of those will determine if her Brexit deal succeeds, whether the UK could be headed for no deal, a second referendum, or even a general election.
But first MPs will vote today on whether to hold ministers in “contempt of parliament” for refusing to publish the full legal advice given to the government on its Brexit deal.
On Monday, the attorney general refused to, saying it was not in the “public interest”.
But six political parties – Labour, the DUP, SNP, Liberal Democrats, Plaid Cymru and the Greens – said an earlier vote calling for the full advice to be published is not being honoured.
When the contempt debate and vote are over, attention will move to the first day’s debate on the EU withdrawal agreement.
Speaking at its opening, Mrs May will hail the 2016 referendum result to leave the EU as “the biggest democratic exercise in our history”.
She is expected to say: “To deliver on that vote, we need to deliver a Brexit that respects the decision of the British people – a Brexit that takes back control of our borders, laws and money.”
Mrs May will add that Britons “want us to get on with a deal that honours the referendum and allows us to come together again as a country, whichever way we voted”.
And she will insist: “This is the deal that delivers for the British people.”
Sky News data-crunching signals Mrs May will fall short of the 320 MPs she needs to win the vote on 11 December.
Some 399 MPs look set to reject or abstain on the “meaningful vote”.
Mrs May’s appearance in the Commons on Tuesday will coincide with a presentation at the European Court of Justice.
The court is hearing a claim by a cross-party group of Scottish politicians that the UK could reverse Article 50 – the clause that initiated Brexit – without the consent of the 27 other EU member states.